This invention relates to a bill validator used for vending machines, exchanging machines, service machines or the like (hereinafter referred to as "vending machine").
There are generally two types in a bill validator used for this purpose, namely one type in which a bill insertion slit is provided in the upper portion of the bill validator and the other type in which a bill insertion slit is provided in the lower portion thereof, respectively for adapting to a mounting space available in a mounting side (i.e., the vending machine side).
If the same bill validator can be used for both of these types by simply changing disposition of the bill insertion slit from the upper portion to the lower portion or vice versa or by simply turning the bill validator itself upside down, the manufacturing cost of the bill validator will be considerably reduced and besides maintenance of the bill validator will be facilitated.
The mere change in disposition of the bill insertion slit or turning of the bill validator upside down is accompanied by the problem that bills will be scattered during inventory of collected bills. That is, collected bills must be taken out by opening the upper end of a bill collecting section during inventory but such change in disposition of the bill insertion slit or turning of the bill validator upside down will cause the bill collecting section to open in the lower end thereof with resulting scattering of bills.
Further, the bill insertion slit generally has means for preventing a water drop from entering the bill insertion slit from above but it has no preventive means against a water drop entering the bill insertion slit from below and, accordingly, mere turning of the bill validator upside down leaves a problem in waterproof characteristic of the bill validator.
For these reasons, there are the two types of bill validators, i.e., one with the bill insertion slit provided in the upper portion and the other with the bill insertion slit provided in the lower portion despite the fact that both have common devices such as bill discrimination means and bill collection means.
On the other hand, there is a known bill validator (e.g., Japanese Preliminary Patent Publication No. 77288/1985) which comprises conveying means for conveying inserted bills, discrimination means for discriminating a true bill from a false one among inserted bills on the way they are conveyed, temporary retention means for temporarily retaining a bill which has been judged to be a true bill, reverse feeding means for feeding the bill temporarily retained by the temporary retention means reversely to a bill insertion slit in response to a bill return command issued by a vending machine, and accumulation means for stacking the temporarily retained bill in an accumulating box in response to a bill collection command issued by the vending machine.
In this prior art bill validator, a shutter for preventing pulling out of the temporarily retained bill is provided in a post stage of a magnetic sensor which constitutes a component part of the discrimination means. This is because a bill cannot be temporarily retained unless discrimination by the discrimination means has been completed. In the prior art discrimination means, a transmitted light amount sensor for detecting thickness or pattern of the bill and a photo sensor for detecting the size of the bill are provided in the post stage of the magnetic sensor and discrimination of the bill is made on the basis of results of detection by these sensors.
In such prior art bill validator in which the bill pulling out preventing shutter is provided in the post stage of the magnetic sensor, the inserted bill is temporarily held at a position after the bill has passed by the magnetic sensor and this gives rise to the problem that, in returning the temporarily retained bill, the end portion of the bill sometimes fails to smoothly enter a space defined between the magnetic sensor and a pinch roller which is provided for holding the bill in association with the magnetic sensor with a result that the end portion of the bill is folded and the bill cannot be returned to the bill insertion slit or, if the bill has been returned, the returned bill has its end portion wrinkled or cut off. If a spring of a weaker urging force is used for the pinch roller with a view to preventing occurrence of such problem, there arises the inconvenience that the surface of the bill fails to contact the magnetic sensor with resulting failure in obtaining sufficient data for discrimination of the inserted bill.